Or trifling matters like clips working on an entirely different principle (transmission vice reflection) than the method which remains patent encumbered.
Certainly it works on a different principle than that which is patented. At the same time, IANAL, and if the stakes are large enough the question might need an adjudicated answer.
Adjudicated answers, also known as patents, have been separately issued for these very different techniques to accomplish the same underlying goal. The transmission patents are expired for quite sometime however, which is why devices using them can be made cheaply.